<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .triangle_up{
      width: 0;
      height: 0;
      border-left: 50px solid transparent;
      border-right: 50px solid transparent;
      border-bottom: 100px solid red;
    }
    .triangle_right{
      width: 0;
      height: 0;
      border-left: 100px solid red;
      border-top: 50px solid transparent;
      border-bottom: 50px solid transparent;
    }
    .triangle_left{
      width: 0;
      height: 0;
      border-right: 100px solid red;
      border-top: 50px solid transparent;
      border-bottom: 50px solid transparent;
    }
    .triangle_down{
      width: 0;
      height: 0;
      border-right: 50px solid transparent;
      border-left: 50px solid transparent;
      border-top: 100px solid red;
    }
    .triangle_bottomright{
      width: 0;
      height: 0;
      border-bottom: 100px solid red;
      border-left: 100px solid transparent;
    }
    .triangle_bottomleft{
      width: 0;
      height: 0;
      border-bottom: 100px solid red;
      border-right: 100px solid transparent;
    }
    .triangle_topleft{
      width: 0;
      height: 0;
      border-top: 100px solid red;
      border-right: 100px solid transparent;
      margin-top: 20px;
    }
    .triangle_topright{
      width: 0;
      height: 0;
      border-top: 100px solid red;
      border-left: 100px solid transparent;
      margin-top: 20px;
    }
  </style>
</head>
<body>
  <div class="triangle_up"></div>
  <div class="triangle_right"></div>
  <div class="triangle_left"></div>
  <div class="triangle_down"></div>
  <div class="triangle_bottomright"></div>
  <div class="triangle_bottomleft"></div>
  <div class="triangle_topleft"></div>
  <div class="triangle_topright"></div>
</body>
</html>